Trench-excavating machine.



F. S. DOBSON. TRENCH EXCAVATING MACHINE.

APPLl'cATsoN man oec. l. 191s. Patented Aug' 2L MHZ 2 SHEETS-SHEET 2. I

l? lll iNVENTOR ATTORNEY WITN ESS ES N UNITED s'rarasI PATENT orrion. i

:FRANK s. yBonson, oF LAKE onYsrAL, MINNESOTA;

To all whom rma/,y concern.'

TRnNoH-noiavnrine ivraoninn.

Be it known that I, FRANK S, Bonsoir,` a

y citizen of the United States, residing at Lake Crystal, kinthe county' of "Blue Earth andState of Minnesotafhave invented new yand useful Improvements" in TrenchlFikeavating Machines", of which the following is a specification. g y i This invention relates'to' trench*eXcavating machines andit consists in thernovel features hereinafterdescribed and claimed; An object of the invention'isy topro'vide amachine adapted to be used :in soft or sandy soil for the purpose ofy cutting a trench, the partssov arranged that as the ktrench is being out the same may be walled up by"usin`g` kplanking or `other supports whereby'thel sides of the trench are pirevented from caving in asthe' machineY progresses. y 'f With this object in view they machine includes a boom with means for raisingand `lowering-the same. y Chains are mounted for movement around rollers" or drums located at the opposite ends ftheboom and suitable kmeans yare provided for rotating the upper roller. Plow points are carried by y thech'ains and scrapers are mounted v.upon

`thefnhains between;the;` said plow: points.

Cutting bladesare pivotally mounteduponl the chains beyondfthe sides of plow point'and are 'adapted te swing in an outward direction asthey move in an upward direction from the bottom` ofthetrench and the said blades are adapted to swing'by gravity overthe chains` as `they `descend r,thereby providing space through which the "planking may be inserted for the purpose of holding the side walls of the `trench againstcaving in as itis being cut.

In the accompanying drawing 2.- y Figure l is a sideelevation of the trench excavating machine; y

Fig. 2 is a top plan view ofk the boom thereof with parts in section. p

Fig. 3 isa longitudinal sectional view of the boom;y

Fig. 4 is a perspective view of a plow point used on the machine. l

` Fig. 5'is a detailed perspective view of one ofthe links of one of the chains.

Fig. 6 is a perspective `view of the scraper. Fig.` 7 is a perspective view of a scoop used on thefmachine. f

Fig. Sis `a perspective View of a blade used on the machine, y

Specification of Letters Patent. ulg, ,i i915'. Appnatio meiiiecmiier 1, iie. 'si-iaiivo'.' leidet. n

The machine comprises ya frame 1 which Indunted at its forward portion upon 8 i'sj'ournaled upon the inasty structure f6 and is rotated ineaiisof ay Chain 9 whieh passes around alsp'iocket wheel y10 ino'unted on the shaft and which in is operativelyfconnected with the engine 4 yin a suitable Irianr1er.` j A belt 11 mounted for movement transversely across 'the rearpon` tio'n` 'of the franie 1 and is adaptedto be operated from' the shaft Sby the means 'of a" chain l2 and 4suitable connecting wheels as best shown in Fig; 1 of the drawing. y

A scoop 13 is mounted at the rearend off the` framevv l .and its rearfend is adapted to trail along the surface df, the ground;

upper forward edge f tthe said'scop prof jects `slightly over the rear kofthebelt n grown in Fig. 1; Artem 14n pivot; i

any @erected its appar reruns end Wan are shaft s aaa as iewered is'aa'apt;

edtof'be swung vertieally. A cable 15 is connected at one einer with the lower portion of the said boin and` is' trained overy the pulleys 7 and arranged to wind upbn a' drum 16 4mounted* on the frame 1l and may be used for' raising and lotteria-g the" free end portion of the said boom.k A shaft 17 is journaled for rotation at thelower rear end of the boom 111 and disks 18 are Carried by the shaft 17. Similar disks 19 are mounted upon the shaft 8 and the disks 18 and 19 yare in alinement with each other..

Chains 2O are trained around the alined disks 18 and 19 and are arranged to move i along the boom llgwhen the shaft 8 isrotated.

Some of the links Lof the chainsQO are,

vadapted to penetrate in the ground during the operation of cutting thet1 .^encl1`. Scraper lchains 20. The links 25 are provided at their outer edges with outstanding lugs 27 and at their innerkedges with outstanding lugs 28. VThe lugs 27 are located in the vicinity of the point of pivotal connection between the said links andthe cutting blades and are adapted to limit the outward swing` ing movement of the blades while the lugs 28 are located more remote from the point of pivotal connection between the blades and the said links and are adapted to limit the swinging movement of the blades.

As the plow point 22 and the. Scrapers 24C move in an upper direction under the boom 14 they encounter the earth and the said points loosen the earth which is caught up by the Scrapers and carried into the scoop 13. After a certain quantity of earth has been accumulated in the said scoop and as additional quantities yare supplied thereto the earth is forced from the scoopl up over the upper edge thereof and deposited upon the upper run of the belt 11 which carries it to one side of the machine and dumps it at the surface yof the ground. When `the blades 26 pass under the shaft 17 and come in contact with the earth they are swung outwardly at their free ends until their outer surfaces come in Contact with the forward end of the lugs 27. Thus the said blades cut the earth beyond the sides of the chains 2O and the earth so loosened is directed in an Copies of thispatent may be obtained for Cutinward direction and is caught up by the scrapers and carried to the scoop 13 as hereinbefore described. When the cutting blades 26 'pass over the shaft 8 their free ends swing in inward directions by gravity until the sides of the said blades encounter the vsides of the lugs 28 and thus the said blades 26 as they move in a downward direction along the upper edge of the boom 14e are swung in beyond the outer side edges of the chains 20 and therefore planking or other similar material may be applied to the side walls of the trench along the upper runs of the chains 20 and thus prevent the walls from caving in while the trench is being cut. Thus it Awill be seen that the machine may be used to advantage for digging a trench in soft ground in quick sand in view of the fact that the walls of the trench may be braced in close proximity to the points in the earth where the cutting operation takes place.

Having described the invention what is 1. In a machine of the character described, a boom, chains mounted for movement along the boom, plow points carried by the chains, and cutting blades pivotally mounted upon the chains at the opposite sides of the plow points and adapted to swing transversely of. the chains.

2. In a machine of the character described,I a boom, chains mounted for movementalong the boom, plow points mounted upon the chains, cutting blades pivotally mounted upon the chains for swinging movement transversely thereof and lugs mounted upon the chains at the opposite sides of the said cutting blades and adapted to limit the swinging movement thereof.

In testimony whereof I affix my signature.

FRANK S. DOBSON.

five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

